The spatial water quality data (281x22) obtained from 12 sampling stations located along the Terengganu River and its main tributaries were evaluated with environmetric methods. Principal component analysis was used to investigate the origin of each variable due to land use and human activities based on the three clustered regions obtained from the hierarchical agglomerative cluster analysis. Six principal components (PCs) were obtained, where six varimax factor (VF) of values more than 0.70 that considered strong loading are discussed. The possible pollution sources identified are of anthropogenic sources, mainly municipal waste, surface runoff, agricultural runoff, organic pollution and urban storm runoff. As a conclusion, the application of environmetric methods could reveal important information on the spatial variability of a large and complex river water quality data in order to control pollution sources.

Pangasius sp. were determined using microwave-assisted digestion/inductively coupled plasma-mass spectrometry. The clustering tendency related to elemental patterns associated with tissue variants and fish habitats were explored using hierarchical cluster analysis and principal component analysis. The results revealed that the general elemental accumulation pattern was strongly dependent on the type of tissue, whereas latent deviations within particular tissue samples can be linked to the natural variability between wild-caught and farmed fish. The inherent elemental patterns allowed us to differentiate between those wild-caught and farmed fish through linear discrimination analysis with 100% precision. In terms of food safety, the elemental concentrations in edible muscle were found to be far below the legal limits, as the associated health risks at the 90th percentile were well within tolerable regions, although wild-caught fish were found to pose a higher risk.

The spatial distributions of Na, Mg, K, Ca, Cr, Fe, Ni, Cu, Zn, As, Se and Pb in Hemibagrus sp. from Selangor River and a reference site were determined with inductively coupled plasma-mass spectrometer, in comparison to the levels in their surrounding water body and sediments. The results demonstrated significant differences in elemental accumulation pattern in different fish tissues originated from both sites. The variations observed were mainly subjected to their metabolic activities, and also the influence of the surrounding medium. In general, the liver tends to accumulate higher concentration of metals followed by the gills, and muscle tissues. The data also indicate associations between the concentrations of metal contaminants measured in the fish and the levels observed at the sites. The concentrations of hazardous metals As, Se and Pb in all the studied tissues reflect the influence of anthropogenic inputs. This suggests the potential utility of widely available Hemibagrus sp. as a valuable bioindicator of metal pollution in environmental monitoring and assessment.

In the present study, the concentration of Cr, Cd, Cu, Zn, Pb, and As in various tissues of Hemibagrus sp. from two different habitat were determined with microwave assisted digestion-inductively coupled plasma-mass spectrometry. The objective of this research was to determine the differences between wild and cultivated in terms of heavy metal accumulation in muscle, liver and gills tissues. The metals accumulation pattern relating types of tissue and elements as well as fish habitats were revealed by principal component analysis. The results revealed that variation in metal accumulation pattern is strongly dependent on the type of tissues. The results suggested that Cu, Zn, and Pb are highly associated with liver tissue while Cr and As with muscle and gills. The differences in heavy metal accumulation observed between wild and cultivated Hemibagrus sp. were probably due to the differences in their environmental conditions. Keywords: principal component analysis, pattern recognition, heavy metal, fish, farmed Abstrak Kepekatan Cr, Cd, Cu, Zn, Pb, dan As dalam pelbagai tisu Hemibagrus sp. dari dua habitat yang berlainan adalah ditentukan dengan pencernaan bantuan gelombang mikro-plasma gadingan teraruh-jirim spektrometri. Objektif kajian ini adalah untuk menentukan perbezaan antara ikan dari habitat semulajadi dan kolam ternakan dari segi pengumpulan logam berat dalam tisu, hati, dan insang. Corak pengumpulan logam berkaitan jenis tisu dan elemen kajian serta habitat ikan ditunjukkan oleh analisis komponen utama. Keputusan menunjukkan bahawa perubahan dalam corak pengumpulan logam adalah bergantung kepada jenis tisu. Keputusan kajian mencadangkan bahawa elemen Cu, Zn, dan Pb adalah berkaitan dengan organ hati manakala elemen Cr dan As adalah berkaitan dengan tisu dan insang. Perbezaan dalam pengumpulan logam berat di antara Hemibagrus sp. dari habitat liar dan kolam ternakan adalah mungkin disebabkan oleh perbezaan dalam keadaan persekitaran mereka.

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